Magento – How to create admin grid without db collection in Magento – 2

Your grid.php file as below:

<?php

namespace Vendor\Modulename\Block\Adminhtml\Report;

/**
 * Adminhtml report grid block
 *
 * @author      Magento Core Team <core@magentocommerce.com>
 * @SuppressWarnings(PHPMD.DepthOfInheritance)
 */
class Grid extends \Magento\Backend\Block\Widget\Grid\Extended
{

    /**
     * StoreIds
     *
     * @var array
     */
    protected $_storeIds = [];


    /**
     * Resource collection factory
     *
     * @var \Magento\Sales\Model\ResourceModel\Order\Item\CollectionFactory
     */
    protected $_resourceFactory;

    /**
     * Table alias
     *
     * @var string
     */
    protected $_tablealias = 'main_table';

    /**
     * Constructor
     *
     * @param \Magento\Framework\App\Action\Context $context
     * @param \Magento\Backend\Helper\Data $backendHelper
     * @param \Magento\Sales\Model\ResourceModel\Order\Item\CollectionFactory $resourceFactory
     * @param array $data
     */
    public function __construct(
        \Magento\Backend\Block\Template\Context $context,
        \Magento\Backend\Helper\Data $backendHelper,
        \Magento\Sales\Model\ResourceModel\Order\Item\CollectionFactory $resourceFactory,
        array $data = []
    ) {
        $this->_resourceFactory = $resourceFactory;
        parent::__construct($context, $backendHelper, $data);
    }

    /**
     * Constructor
     *
     */
    protected function _construct()
    {
        parent::_construct();
        $this->setId('orderbyGrid');
        $this->setFilterVisibility(false);
        $this->setDefaultSort('created_at');
    }

    /**
     * Collection
     *
     */
    protected function _prepareCollection()
    {
        //$collection = $this->_resourceFactory->create();

        $collection = 'your collection from web service';
        $this->setCollection($collection);
        return parent::_prepareCollection();
    }


    /**
     * {@inheritdoc}
     *
     * @SuppressWarnings(PHPMD.ExcessiveMethodLength)
     */
    protected function _prepareColumns()
    {
        $this->addColumn(
            'created_at',
            [
                'header' => __('Interval'),
                'index' => 'created_at',
                'sortable' => false,
                'filter'    => false,
                'period_type' => $this->getPeriodType(),
                'renderer' => 'Magento\Reports\Block\Adminhtml\Sales\Grid\Column\Renderer\Date',
                'totals_label' => __('Total'),
                'html_decorators' => ['nobr'],
                'header_css_class' => 'col-period',
                'column_css_class' => 'col-period'
            ]
        );

        $this->addColumn(
            'orders_count',
            [
                'header' => __('Orders'),
                'index' => 'orders_count',
                'type' => 'number',
                'total' => 'sum',
                'sortable' => false,
                'filter'    => false,
                'header_css_class' => 'col-orders',
                'column_css_class' => 'col-orders'
            ]
        );

        $this->addColumn(
            'total_qty_ordered',
            [
                'header' => __('Sales Items'),
                'index' => 'total_qty_ordered',
                'type' => 'number',
                'total' => 'sum',
                'sortable' => false,
                'filter'    => false,
                'header_css_class' => 'col-sales-items',
                'column_css_class' => 'col-sales-items'
            ]
        );

        if ($this->getFilterData()->getStoreIds()) {
            $this->setStoreIds(explode(',', $this->getFilterData()->getStoreIds()));
        }
        $currencyCode = $this->getCurrentCurrencyCode();
        $rate = $this->getRate($currencyCode);

        $this->addColumn(
            'total_base_price',
            [
                'header' => __('Sales Total'),
                'type' => 'currency',
                'currency_code' => $currencyCode,
                'index' => 'total_base_price',
                'total' => 'sum',
                'sortable' => false,
                'filter'    => false,
                'rate' => $rate,
                'header_css_class' => 'col-sales-total',
                'column_css_class' => 'col-sales-total'
            ]
        );

        $this->addColumn(
            'total_row_invoiced',
            [
                'header' => __('Invoiced'),
                'type' => 'currency',
                'currency_code' => $currencyCode,
                'index' => 'total_row_invoiced',
                'total' => 'sum',
                'sortable' => false,
                'filter'    => false,
                'rate' => $rate,
                'header_css_class' => 'col-invoiced',
                'column_css_class' => 'col-invoiced'
            ]
        );

        $this->addColumn(
            'total_price_incl_tax',
            [
                'header' => __('Paid'),
                'type' => 'currency',
                'currency_code' => $currencyCode,
                'index' => 'total_price_incl_tax',
                'total' => 'sum',
                'sortable' => false,
                'filter'    => false,
                'visibility_filter' => ['show_actual_columns'],
                'rate' => $rate,
                'header_css_class' => 'col-paid',
                'column_css_class' => 'col-paid'
            ]
        );

        $this->addColumn(
            'total_amount_refunded',
            [
                'header' => __('Refunded'),
                'type' => 'currency',
                'currency_code' => $currencyCode,
                'index' => 'total_amount_refunded',
                'total' => 'sum',
                'sortable' => false,
                'filter'    => false,
                'rate' => $rate,
                'header_css_class' => 'col-refunded',
                'column_css_class' => 'col-refunded'
            ]
        );

        $this->addColumn(
            'total_tax_amount',
            [
                'header' => __('Sales Tax'),
                'type' => 'currency',
                'currency_code' => $currencyCode,
                'index' => 'total_tax_amount',
                'total' => 'sum',
                'sortable' => false,
                'filter'    => false,
                'rate' => $rate,
                'header_css_class' => 'col-sales-tax',
                'column_css_class' => 'col-sales-tax'
            ]
        );

        $this->addColumn(
            'total_base_shipping_amount',
            [
                'header' => __('Sales Shipping'),
                'type' => 'currency',
                'currency_code' => $currencyCode,
                'index' => 'total_base_shipping_amount',
                'total' => 'sum',
                'sortable' => false,
                'filter'    => false,
                'rate' => $rate,
                'header_css_class' => 'col-sales-shipping',
                'column_css_class' => 'col-sales-shipping'
            ]
        );

        $this->addColumn(
            'total_discount_amount',
            [
                'header' => __('Sales Discount'),
                'type' => 'currency',
                'currency_code' => $currencyCode,
                'index' => 'total_discount_amount',
                'total' => 'sum',
                'sortable' => false,
                'filter'    => false,
                'rate' => $rate,
                'header_css_class' => 'col-sales-discount',
                'column_css_class' => 'col-sales-discount'
            ]
        );

        $this->addExportType('*/*/exportSalesCsv', __('CSV'));
        $this->addExportType('*/*/exportSalesExcel', __('Excel XML'));

        return parent::_prepareColumns();
    }

    /**
     * Get allowed store ids array intersected with selected scope in store switcher
     *
     * @return array
     */
    protected function _getStoreIds()
    {
        $filterData = $this->getFilterData();
        if ($filterData) {
            $storeIds = explode(',', $filterData->getData('store_ids'));
        } else {
            $storeIds = [];
        }
        // By default storeIds array contains only allowed stores
        $allowedStoreIds = array_keys($this->_storeManager->getStores());
        // And then array_intersect with post data for prevent unauthorized stores reports
        $storeIds = array_intersect($allowedStoreIds, $storeIds);
        // If selected all websites or unauthorized stores use only allowed
        if (empty($storeIds)) {
            $storeIds = $allowedStoreIds;
        }
        // reset array keys
        $storeIds = array_values($storeIds);

        return $storeIds;
    }

}